Keloid: benign overgrowths of scar tissue

Keloids are raised, benign scars that extend beyond the original wound. This article explains appearance, causes, risk factors, differences from hypertrophic scarring, and typical management options.

Overview

A keloid is an abnormal scar that forms after skin damage such as a cut, burn, acne lesion or surgical wound. Unlike a typical scar, a keloid grows beyond the boundaries of the original wound and often persists or enlarges over time. Keloids are benign (non‑cancerous) but can cause itching, discomfort and cosmetic concern.

Appearance and common sites

Keloids are usually firm, smooth, shiny and raised above the skin. Their color varies from pink to dark brown depending on skin tone. They may be irregular in shape and sometimes reach large sizes. Common locations include the chest, shoulders, upper back, earlobes, and jawline.

Causes and risk factors

Keloids result from an exaggerated healing response in which connective tissue (collagen) is produced in excess. Risk factors include a family history of keloids, darker skin types, younger age (often developing during adolescence and early adulthood), and certain types of trauma such as burns, piercings or surgical incisions. Sometimes a small, seemingly trivial injury will trigger a large keloid.

Characteristics and diagnosis

Grow beyond the original wound margins (distinguishes them from hypertrophic scars).
May be itchy, tender or even painful.
Do not typically resolve without treatment and have a tendency to recur after removal.

Treatment and prevention

Treatment options aim to reduce size, symptoms and recurrence. Approaches commonly used include pressure therapy, silicone gel sheets, intralesional corticosteroid injections, cryotherapy, laser treatments, surgical excision (often combined with adjuvant measures), and, in selected cases, low‑dose radiation after surgery. No single therapy is universally curative, and management is tailored to the lesion, location and patient preference. Preventive strategies include careful wound care and avoiding elective skin trauma (for example, body piercings) in people known to form keloids.

Keloids can have a substantial cosmetic and psychological impact, especially when visible. They are benign but may be mistaken for other skin conditions; a clinician will usually diagnose a keloid by appearance and history. Research continues into the cellular mechanisms that drive excessive scar formation and into more effective preventive and therapeutic options.